Fluid pressure means and system



Sept. 16, 1941. c. M. KENDRICK FLUID PRESSURE MEANS AND SYSTEMV Filed May 5, 1959 4 sheeis-sheet 1 SePt16, 1941. c. M, KENDRICK 2,255,782

FLUID PRESSU-RE MEANS AND SYSTEM Filed May 5, 1959 4 Sheets-Sheet 2 INVENTOR Char/es /I/l. /fendr/'a/r Sept. 16, 1941. c. M. KENDRICK v FLUID PRESSURE MEANS AND SYSTEM Filed May 5, 1939 4 Sheets-Sheet 5 Rim Oe E T` N N R WM o ma n l Sept 16, 1941. c. M ICK 2,255,782l

Patented Sept. 1.6, 1941 ,UNIT-Ep' sTA'ri-:s APML-:NT 'OFFICE zzssnsz l I v FLUID PBESSUBE MEANS AND SYSTEM Charles M. Kendrick, Newv York, N. Y., alsignor to Manly Corporation, Washington, D. C., a cor- A poration of Delaware Application, May 5, 1939, Serial No. 271,874

p is. claims. This invention, relates to fluid pressure devices and systems which are adapted to transmit power v by] means of fluid under pressure. t

The widest present use for devices and systems of this general class is as hydraulic devices and systems, that is to say. devices and systems for s handling, or whose motive fluid is a liquid, such, for example, as oil. The present invention will accordingly 'be described in connection with such use, although it will be understood that the invention is also applicable to devices and systems operating with elastic fluids.

In uid pressure devices'and systems oi the type under consideration itis frequently necessary or desirable to employ operatingv pressure fluids having dierent but related pressures. This is the case, for` example, when the uid system includes a fluid motor `i the vane type in which the vanes move inw and outward of the rotor in a substantially radial direction. In vane motors oi this character it is often necessary to force the vanes radially outward during certain portions of their rotary travel, particularly at starting and when the motor is operating at low rotative speeds, so that the outer ends oi the vanes will be held ilrmly in contact with the surrounding vane track and thus provide a movable resistance to the pressure iluid admitted to the pressure areas at the outer ends oi the vanes of the iiuid motor, whereby rotary motion is imparted to the rotor and the driven shaft of the vane motor. A highly practical and satisfactory method for forcing the vanes oi the motor radially outward against 'the vane track is by introducing or admitting, behind the inner ends of the vanes. pressure fluid having a pressure greater than but related to the pressure of the fluid admitted to the pressure areas at the outer ends of said vanes, as fully explained in my copending application filed March 28, 1938, Serial Number 198,449. Thus iluid under two different but related operating pressures is used; the

' iluid having the higher of these two pressures,

which tor convenience is termed the dierential high pressure fluid, is admitted to the radially inner'ends oi the vanes, while uid under the lesser of these two pressures is -admitted to the pressure areas at the outer ends of the vanes of These two diilerent but related pressures have heretofore been provided by two methods disclosed in the above mentioned application. According to' one method, the whole supply or fluid going to the vanemotor is passed through a diimaintains the pressure ofthe uid in its inle port at a value exceeding by a substantially constant amount or diiierential the pressure oi' the fluid in its outlet port. 'Ihis method-has been found to work very satisfactorily but it involves a power loss incident to the pressure drop across the differential pressure" valve and this loss applies to the greater portion of the total iluid supply (i. e., the entire portion oi the iluid that passes to the pressure areas at the outer ends or the vanes) as only a relatively small part of the total is supplied to the inner ends of the vanes at the differential high pressure value existing in the valves inlet port.

According to the second of these two methods, a separate, auxiliary pump is employed to boost the pressure of the uid supplied to the inner ends of the vanes to a value exceeding by a substantially constant amount the pressure of the iluid that passes to the outer ends of the vanes. This method is more eiilcient, as a general rule, than that of passing the entire fluid volume through a diirerential pressure valve but it requires a separate booster pump and, when this pump is operated at a constant speed, as is usually the case, it also has the handicap oi providing a substantially constant supply of difierential high pressure, fluid" irrespective oi the speed at which the vane motor is being operated and irrespective ot the volume of iluid required for the inner ends of the motors vanes.

An object oi! the present invention is to proyvide a fluid pressure device and system of the character above indicated in which one rotary piston element pump, for example a vane type pump, delivers iluid at two diirerent pressures. one of said pressures being related to but greater than the other. l

Another object is to provide a iluid pressure device and system of. this character in which the volume of uid delivered at each'of these two pressures may be coniormably and simultaneously varied from minimum to maximum.

A further and more speciilc object is to provide a fluid system of this character that includes a vane type pump 'and a vane type fluid motor and in which the vane type pump supplies iluid at one pressure for admission to the pressure areasoi the vane motor to act upon the exposed outer ends of the vanes and also supplies iiuid at a higher but related pressure to be admitted to the ierential pressure or resistance valve which unit characterized byits elciency in operation,

co-pending application filed February 12, 1941, i Serial Number 378,524, in which certain parts of 1 the subject-matter thereof are claimed.

2 l l :intrigas its compactness, and the economy of manufacture. y

Other and more speciiic'obiects will appear from the description which follows.

The invention will be understood from consid- 5 eration of the accompanying drawings which illustrate, by way of example, embodiments of the present invention.

,In the drawings: v

Fig. 1 is a view, partly diagrammatic and partly l0 in section, including a longitudinal sectional view of a rotary piston-element pump unit taken along the line I-I of'Fig. 2 and also including a corref spondinglongitudinal sectional view of a rotary piston element motor unit taken along the line 15 I-I of Fig. 3;

Fig. 2 is a view of the pump unit, in vertical transverse section, taken along the line 2-2 of Fig. 1;

Fig. 2a is a view of one of the end plate ele- 20 l ments of the pump unit showing the face thereof adjacent thel rotor;

Fig. 2b is a view of the other of the end plate elements ofthe pump unit, showing -the .face thereof adjacent the rotor; 25

Fig. 3 is a view of the motor unit, in vertical transverse section, taken along the line 3-3 of l Fig. 1:

Fig. 3a'is a view of one of the end plate elements of the motor unit showing the face thereof 3 adjacent the rotor;

. and

Fig. 4a a transverse sectional view along the I une sa-aa or Fig. 4.

Figs. 1, 2, 2a, 2b, 3 and 3a are also shown m40 Referring now to these drawings, as shown in Fig. 1, I have illustrated the present invention,` as embodied in a iluid system including a rotary 45 piston element pump, here shown as a vane type pump A, and a rotary element iluid motor, here l shown as a vane type fluid motor B. The pump A j and the motor B may both be of xed sti-oke" or 3 capacity per revolution or both of them may be 50 of variable stroke, or one may be of variable stroke and the other of xed stroke. In the present embodiment I have shown the pump A as of E variable stroke and the motor Bas of 'xed l stroke, as will be hereinafter more fully explained. 55

In the particular embodiment of pump structure shown the pump casing is in two' axially 1 separable parts III and II (Fig. l) which are suit-f 1 ably `fastened together as by cap screws, not o0 shown, and which cooperate to form a cavity for therotor I5 and associated parts. The rotor I5 j is rotatably supportedby its hubs I3 which exl tend into bushings Il carried by the casing parts I0 and I I respectively and said rotor also has a slidable splined connection with the driving shaft vanes I9 form substantially fluid-tight running iits with the adiacent faces of said end plates. 76

The end plates 23 and 24 are provided with holes at their centers through' which pass the rotor hubs I8, and are also provided with ports and fluid passages to be later described. e

As best shown in Fig. 2 the pump A is a rotary piston multi-section or part Dump consisting of two pumping sections o'r halves which are separated from each other by fixed abutments Il and which discharge into a common discharge channel 45, to be presently described. The rotor I5 is provided with a multiplicity of vane-slots I3 in each of which is a vane I3 adapted to move radially inward and outward therein as the rotor revolves. The radially outward'ends of the vane Il follow a trackway that controls their inward and outward movement and which comprises the two fixed abutments 30, two movable abutments 3I and connecting flexible track elements 34. The movable abutments are slidably supported in slideways 33 formed in the spacer ring I4 on the interior of the casing and are adapted to be radially adjusted with respect to the circumferential rotor surface. The work of pumping by the exposed outer ends of the vane I9 is done as the vanes move across an arc 32 on each movable abutment, termed the working or "pumping arc, the fluid being received at one end of this arc and discharged at the other. Regulation of the stroke or volumetric capacity per revolution of the pump is effected by moving or radially adjusting the movable abutments 3l to vary the distance separating the pumping arcs 32 from the circumferential rotorsurface; the flexible track elements 34 have extensible connections with the fixed abutments 30 thereby permitting adjustment of the movable abutments 3l without change of position ofsaid fixed abut--l ments 33.

The movable abutments v3| are adapted to be moved by means of a pair of adjusting rods 35 which are attached thereto as by the pivot pins 38. The adjusting rods extend through suitable holes in the spacer ring I4 and in the side covers I2 which close the horizontal adjusting rod bores formed in the casing part I0. Movement or adjustment of the adjusting rods 35 and movable abutments 3| may be effected by any suitable means, not shown, which may be conveniently connected with the links 31 on the outer ends of the adjusting rods. It'will be understood that the volume of iluid'pumped by the outer ends of the vanes of each pumping section is dependent upon the distance between the circumferential surface of the rotor I5 and the pumping arc 32 of the corresponding movable abutment 3| so that the output of veach half of the pumping section may be infinitely varied at will. It will also be understood that the total volume of fluid i Serial N0. 366,931 led NOV. 23, 1940, which is in part a continuation of application, Serial No. 247,586, filed Dec. 24, 1938.

As already stated, fluid is admitted to the pumping chambers or pumping arcs at the lsides of the vanes as they approach each pumping arc and fluid is discharged from the pumping chamber 'in like manner as the vanes recede therefrom.

In the emiwiiineni: of ma. i and 2, au admission and discharge to and from the outer ends of the vanes il is accomplished through ports in the and 2b as recessed and not iextending through the. end plate 24)- which serve principally as balance ports to contain riuid under the same pressure as that in the corresponding ports in the end plate 23 in order to substantially balance rates of inward and outward movementof the its regions ci least diameter and concentric working arcs or chambers 32' at its regionsof greatest diameter, the arcs 30' and 32' being :loinedby intermediate connecting portions 33.' of any suitable curvature producing satisfactory vanes i9' as the rotor Il revolves.

Pressure duid isadmitted to the exposed outer ends of the vanes il' as they approach thework-- ing arcs 32' 4and acts against the exposed outer ends of said vanes as they move acrosssaid working arcs, thus imparting rotary motion to' the the Hydraulic forces aotingon the sides or axial ends of the vanes 'to prevent bindingthereof.

Fach outlet port 23 of the end plate 23 registers with asimilar port formed in the side walls of the casing member Il which is connected by a slanted passage 33 with the outlet conduit I5 as shown in Fig. 1. The outlet'condult 4l is suitably connected, as indicated by the dotted lines` at 4l in Fig. 1, with a passage 33 leading to the vane motor B. The inlet ports A2li of the end "plate 23 are similarly connected with the inlet conduit I3 or they may be connected therewith in any other suitable manner, and the conduit 43 is connected with the uid supply pipe I2, as indicated by the dotted lines at Ii in Fig. 1, which may be connected with a suitable reservoir, not shown.

When the rotor I5 revolves in a counter-clockwise direction as viewed in Fig. 2 iluid enters through the inlet ports 25 of the end plate 23 and passes between the outer ends of those vanes I9 that are in the inlet area of each of the two pumping sections of the pump. Pumping is acrotor il and the driven shaft 23'. Fluidfis discharged rrom the outer ends or the vanes il' as they recede from the working arcs 32'. Ail admission and exhaust to and from the outer ends of the vanes I9' is accomplished through inlet and outlet ports in the end plate 23' identicalv in arrangement with the already described ,90m of the pumps end .plate 23 as will be evident from Fig. 3a, but it will be noted that the ports complished by the rotary motion of the outerends of the vanes i3 as they sweep across the pumping arcs 32, said vanes I3 thus forcing fluid into the outlet area of each of the two pumping sections from which it out through the outlet ports 23 of the end plate 23 and into the discharge channel 4l. As already stated, the size of the pumping chambers and the volume of fluid delivered by the pump are determined by the distance of the pumping arcs 32 from the rotor i5; as this distance may be varied in inilnitely small increments from minimum to maximum, the size of the .pumping chambers, and hence the volume of uid pumped by the outer ends of the vanes, may likewise be varied from minimum to maximum.

The structure of the motor B (Fig. 1) is identical with that as already described in connection with the pump A except in certain parts to be presently explained. For convenience in distinguishing between pump and motor parts in the explanation which follows, the parts of the motor which are identical with those of the pump have been designated by the same reference numeral by adding "prime as for example the rotor of the pump A is designated by the reference numeral I5 and the rotor of the motor B by the reference numeral i5', etc.

. The motor B as here illustrated is also a rotary piston multi-section or part device asbest shown in Fig. 3, but as already stated is of iixed stroke or capacity per revolution. It is accordingly provided with a non-adjustable vane track comprisying a vane track ring Il having an interior vanecontacting track or surface. The vane track surface may be given any suitable contour but is preferably provided with concentric arcs 33' at 25' of the motor B are the high pressure ports and that the discharge ports 2l' are its low pressure ports whereas the reverse relative pressure condition exists in th'e inlet ports 2l and outlet ports 26 of the pump A..

The inlet ports 25' in the end plate 23' of the motor B are connected with the motors inlet channel 43 by means of registering ports in the side walls of the casing member ill' and slanted passages 33', as plainly shown in Fig. 1 wherein a fsectional view through the ports 2l' is illustrated.

The inlet channel I3. of the motor B is connected with the passage 39 leading from the pump A as indicated by the dotted lines Il' of Fig. l. The discharge ports 26' of the end plate 23' are connected in a similar manner. not4 shown, with the discharge channel Il' which in turn is connected with the return passage 43, as indicated by the dotted lines at ll", which leads to the reservoir, -not shown. In this connection it may be pointed out that the iiuid passages between the outlet channels of the motor B and the corresponding ports 23' in the end plate 23' are identical with the corresponding outlet passages of the pump A: the sectional view of the motor B is taken through its inlet areas whereas the sectional view of the pump A is taken through4 its outlet area so that thev exact arrangement of i all ports and passages may be readily understood therefrom, although it will be understood that these exact arrangements are not necessary and may be varied if desired. The end plate 24 is also provided with recessed inlet'ports 25 and outlet ports 26', similar to the ports in the pump end plate 24; these ports in the end plate 24' serve principally as balance ports, as all fluid lis admitted to and exhausted from the outer ends of the vanes i9' through the ports of the end plate 23', as already stated. 'I'he particular structure of the vane track ring Il', rotor il' and plates 23' and 24', etc., forms no part of the present application but `a part of application Serial Number 198,449, iiled March 28, 1938, and it will be understood that any other suitable structure may be employed.

With the parts of the motor B in the position illustrated in Fig. 3 and with the pump A in operation and adjusted so that fluid is. being pumped by the outer ends of its vanes i9, pressure iiuid from the pump A will enter the inlet ports 2l' of the motor B and rotate the rotor I5' and driven shaft 20' in a clockwise direction as viewed in Fig.

' 3. 'I'he speed of rotation of the rotor II' of the motor B is determined by the volume of fluid adma to the outer ends of us vanes n' wmcnm l is determined by the volume oi' iluid delivered thereto by the pump A; the speed of rota- 3 tion of the rotor Il' of the motor AB may thus be infinitely varied from minimum to maximum by 1- corresponding variation in theoutput of the pump A. In order for operation to take place however, it is necessary that the vanes I'. be1 1 rmlyin contact with the vane track surface at the werking arcs sz' and that there be similar 1 contact between the ends of the vanes Il' and the vane track at the arcs Il' to thereby separate the two fluid sections of the motor B. This contact between the :vanes I.' and the vane track is accomplished by lintroducing behind'the radially inner ends of said vanes II' fluidhaving a pressure greater than but correlated with the pressure of the fluid admitted to the inlet ports 2B. l -means by which this higher pressure uid (for 'Ihe convenience hereafter termed "dierential high Q pressure fiuid") is produced and its pressure regulated and bz2' which it issupplied to the inner ends of the vanes. II' of the motor B are `im portant features of the present invention and will now be described.

Referring now t'o Fig. 2a. the pump end plates 1 22 and 24 are each formed with two pairs of arcuate recesses or grooves 21 and 2l in the'faces 1 thereof adjacent the rotor Il. 'I'hese recesses 21 i and 2l are' positioned to register successively with the inner ends of the vane slots I8 as the rotor Il revolves and they act as ports or passages for` fluid to and from said vane slots II and j hence are termed vane slot ports."

The vane slot ports 21are connected with the inlet ports 25 by radial passages or grooves 29 1 1 on the outer faces of the end plates 23 and 2| and 1 the length of said vane slot ports 21 is such that 1 the inner ends of each vane slot I8 connects 3 therewith during the time that the outer end of its corresponding vane I! ismoving across the inlet areas of the pump A and is approaching the 1 pumping arcs 22. The inner end of each vane 1 slot II is thus illled with fluid as its corresponding vane I 9 moves radially outward under the 1 action of centrifugal force while said vane I9 is passing'from each xed abutment 30 towar i the contiguous pumping arc l2. 1'

i flexible interconnecting track element Il that lies in each of the inlet areas of the pump A; the inner end of cach vane slot II is thus connected with the fluid inlet supply during the time that 1 its corresponding vane Il is moving through the such length that they also connect'with the inner ends of those vane slots Il whose vanes I9 are in 'contact with the pumping arcs I2 and the fixed abutments 30 so that fluid pressuris applied to the inner ends of such vanes to assist in holding l their outer ends firmly in contact with the vane track surfaces as said vanes move across the xed and movable abutments. The volume of uid pumped by the inner ends of the vanes I9, per revolution of the rotor I5, for any particular rotor and vane assembly is dependent upon and varies conformably with the stroke of the vanes which. as already explained, is determined by the distance between the pumping arcs 32 and the circumferential rotor surface and may be infinitely varied at will. The volume of fluid pumped by the inner ends of the vanes may thus be infinitely varied from minimum to maximum and variation in the volume pumped by the inner ends of the vanes is effected simultaneously and conformably with variation in the fluid volume pumped by the outer ends of said vanes as they move across the pumping arcs.

Fluid pumped by the inner ends of the vanes Ilof the pump A is utilized to provide the differentialhigh pressure fluid to force the vanes I0 of the motor B radially outward against the vane track. The vane slot ports 28 of the pump A are accordingly .connected in any suitable manner with the vane slot ports 21' of the motors end plate 24'. In the present instance the fluid passages providing this interconnection include a hole 22 in each of the vane slot ports 28 in the pumps end plate 24 and said hole 22 registers with a'passage l1 leading vto a channel 48 formed in the pump casing member II. The channel 48 is connected as by a pipe I9 with a correspond- Fluid entering the inner ends of the vane slots i Il through the vane slot ports 21 as explained 1 above is discharged into the vane slot ports 2l as the outer end of each vane Il moves inward during the time it is passing from the pumping arc 32 of each pumping section through the corresponding outlet area of the pump and on to the 3 contiguous ilxed abutment 3l.

1 derstood by referring to Fig. 2 in which it will 1 be observed that the vanes I9 occupy the exi treme radially outward position when their outer 1 ends are in contact with the pumping arcs 32; it will also be'observed that said vanes I9 are moved progressively inward as said vanes traverse the interconnecting track element Il intermedii ate said pumping arc 32 and the contiguous ilxed abutment Il: and it will further be observed that This will be unthe vanes I! occupy the extreme radially inward It will thus be seen that ing channel 48' in the motor casing member II' and said channel 48' is connected through a passage 41 by a hole 22 with each vane slot port 21' in the motors end plate 24'.

At this point it should be noted that the end plates 23' and 24 of the motor B are provided 'with vane slot ports 21 and 28 corresponding generally to the already described vane slot ports of the pumps end plates. The vane slot ports ofthe motors end plates 23' and 24' differ from those of the pumps end plates however in that the vane slot ports 21 (which in this instance are its high pressure vane slot ports) are not only co-extensive with the inlet ports 25' ybut are preferably of such length that each vane slot I8' connects therewith during the time that the vane I9' therein is traversing the arc 30 and the working arc 32' of each uid section as well as while traversing the intermediate portion 34' of the track that lies in the inlet area of each fluid section of the motor B, as plainly shown in Fig. 3. Fluid entering the inner ends of the vane slots I8 of the rotor I5 is discharged into the vane slot ports 28' which are connected with the outlet ports 26' of the end plates 23' and 24 by radial passages 29' on the outer faces thereof.

In order to assure that the vanes I9 of the motor B are forced radially outward against the vane track it is necessary that the volume of iluid pumped by the inner ends of the vanes I9 of the pump A be equal to or greater than the actual fluid volume required tol` produce such radially outward movement of the vanes I9' of the motor B. That is to say, the volume of iluid pumpedper revolution of the rotor I5 of the pump A by the inner ends of its vanes I9, at any stroke .or capacity of the pump A, must have a relation to the corresponding volume of iluid pumped by the outer ends of said vanes cisely the volumeof fluid required vbythe inner I9 that is equal to or greater than the relation of the iluid volume required for the inner ends of the motors van I9 per revolution of its rotor I5' with respect to the fluid volume that ends'of the motors vanes I9' butin commercial practice this is diiiicult if not impossible of attainment because of variation in leakage, lits of the parts, etc., which will occur as between individual pumps and motors even though made to the same dimensions and close tolerances. In practice therefore it is necessary that the inner ends of the pump's vanes supply fluid in excess of the volume actually required by the inner .ends of the motorsvanes I9'. Thismay be' `accomplished in numerous ways. such, for example, 4as by making the'vanes I9 of the pump A thicker'than the vanes I9' of the motor B must be admitted to the outer ends of the motors vanes I9' in order 'to produce one revolution of the rotor I5. This relation will vary with particular embodiments and is due in part, for instance, to the porting provided for the inner end of the vane slots I4' of the motor B,-

as will be more fully explained lpresently in` connection with the modified end plate 23" shown in Fig. 3b.

With the arrangement illustrated in Figs. 1, 2, 2a, 2b, 3- and 3a, the flow of uid with respect to the inner ends of the vanes of the pump and motor is as follows: Upon rotation of the pump rotor I5 in a counter-clockwise direction, fluid will ilow from the supply pipe 42 into the inlet conduit43, and to the inlet ports 25 of so that the inner en d of each pump. vane has an area greater than that of each motor vane I9'. In the present embodiment however this is accomplished by the simple method of providing thepumps rotor I5 with a greater number of vanes than are provided in the motors rotor I5'; this is clearly shown in' Figs. 2 and 3 in whichit will be observed that the pumps ro'- tor I5 is provided vwith sixteen vanes whereas the motors rotor I5' is provided with twelve vanes. A i

Itis also necessary to provide a path of escape for the excess fluid pumped by the inner the pump's end plate 23, and will ll the spaces Y between the outer ends of the vanes I9 as they pass through the pumps inlet areas. Fluid also passes from the ports 25 of both end plates 23 and v24, through the' radial passages 29 on the outer faces of said end plates, to the vane-slot ports 21 of both end plates and into the inner ends 'of the vane slots I8. As the vanes I9 are moved inwardly while passing across the interconnecting track elements 34 in the outlet areas of the pump, fluid is pumped by the inner ends of said vanes I9 into the vane slot ports 29 of the end plate 24, through the holes or ports 22 in said end plate 24, into the passages 41, the channel 49, the pipe 49 and into the channel 48' of the motor B; thence through the passages 41', 4holes or ports 22 of 'the lend plate 24' vane slot ports 21' of the end plate 24' and thence below the inner ends ofA the vanes I9' to force them outwardly and into contact with the vane track as the rotor I5' of the motor B turns in -a clockwise direction. After passing the y working arcs 32', the vanes I9' are forced inwardly as they pass across the cam surface of the vane tracks intermediate connecting portions 34' that are positioned in the motors outlet areas and uid is discharged by the inner ends of the vanes I9' this iluid passing out through the vane slot ports.23' of both of the end plates 23' and 24', through the radial passages 29' on the outer faces of said end plates and into the outlet ports 26' of both ofthe end the ports 26 of the end plate 24' passes across the rotor through the spaces between the outer ends of the vanes I9', into the`ports 28' of the end plate 23', thence, together with the fluid .plates 23' and 24';'iluid passing out through I discharged by the outer ends of the vanes and the fluid that is discharged by the inner ends of the vanes I 9' through the ports 25' of. the

lend platel 24', into the discharge channel 45' and lly into the return passage or pipe 46. Theoretically it is merely necessary that the inner ends of the pumps vanes I9 supply preing valve C.

ends of the pumps vanes I9 and not required by the inner. ends of the motors vanes I9'. Moreover, it is necessary that the pressurefof the fluid admitted to the inner ends of the vanes I9', to force'them radially outward against late the o'w of uid (i. e., the excess fluid not required by the motors vanes I9') from the passage 49 to the passage 39 in such manner that the pressure of the iiuid in the passage 49 ex-` ceeds'by a substantially constant, predetermined amount the pressure of the fluid in the passage 39 in order to provide dierential high pressure relation to the fluid supplied to the inner ends of the motors vanes I5 with respect to the pressure of the fluid supplied to the -outer ends thereof. The valve C may accordingly assume any 'suitable form of dierential pressure, resistance, relief or pressure reduc valve capable of accomplishing thisfunction. The particular structure of the valve C illustrated in Fig. 1 has been found to function reliably, and satisfactorily in practice and will now be described.

The valve C includes a housing 50 provided with a valve bore in which a valve piston 55 is slidably tted. The valve piston 55 is formed with two heads of unequal diameter, the diameter of the head 54 exceeding the diameter of the head 51, and the valve bore is similarlyl formed with two unequal diameters in order to are of such length that one or the other of them, ls in communication with the valves inlet port in all positions o! adjustment of the valve Piston 55.

1The valve piston .55 is urged toward its fully closed position. in which it is shown in Fig. 1, by a spring 5I, one end of which is received withina recess in the adjacent end of the valve piston 55 and the other end of which bears against a somewhat hat-shaped abutment piece 52. The abutment piece 52 also bears against a screw 59 carried by the cover 54 and said screw 69 provides means by which the compression oi the spring '5| may be adjusted: in the present instance the screw 53 is of the headless type and a pipe plug 54 closes the outer end of the enlarged opening provided for use in adjusting said screws position.

Both ends-of the valve piston 55 are adapted to be acted upon by fluid having the same pressure as that in the valve's outlet port 52. The outlet port- 52 is accordingly connected with the passage 95 which connects with vthe end of the valve bore containing the spring 9| at a point which will not be covered by the head 55 when the valve piston 55 is in its maximum open postion. .A hole or passage 95 extends axially through the valve piston 55 so that both ends of the valve bore will contain uid under the same pressure as that in the valve's outlet port 52.

With this arrangement it -will be seen that the valve piston 55 is urged toward its fully open position (or toward the right as viewed in Fig. 1)

by a fluid-exerted force determined by the pressure of the fluid in the inlet port 5I and equal in amount to the `torce produced by the action of this pressure iluid upon a surface area equal to the difference in the areas of the two heads 59 'and 51. Similarly the valve piston 55 is urged toward its fully closed position (or toward the left as viewed in Fig. 1) by Huid-exerted force determined by the pressure of the fluid in the inlet port 52 and equal in amount to the action of this pressure fluid upon an area equal to the diil'erence in areas of the heads 55 and 51, and this Huid-exerted ,force is supplemented by the force of the spring 5| acting in the same direction.

` The valve piston '55 is accordingly moved by one or the other of these opposing forces whenever they are unbalanced and will be so moved until these opposing forces are made equal to each other by change in the relative pressures in the inlet port 5I and outlet port 52 produced by movement of the valve piston 55. In this manner the valve piston 55 moves ,to regulate the flow of iluid from the passage 49 to the passage 39 to provide pressure in the passage 49 that exceeds the pressure in the passage 99 by an amount determined by the force exerted by the spring 6I. This'relative diil'erence in pressures is maintainedv irrespective of absolute pressures; that is to say, irrespective o1' the actual amounts of the pressures existing in the inlet port 5l and outlet port 52 respectively and, within the limits of the rate of the spring 5I, is likewise maintained substantially constant irrespective oi' the The cover 59 is provided with a narrow flange ,59 which projects into the valve bore and acts as a stop for the valve piston 55 so that substantially all of the adjacent end of the valve `lliston is continuously exposed to pressure uid even when the' valve is in its closed position.

'I'he valve C thus functions to regulate the `now o1' excess iluid pumped by the inner ends of the pumps vanes I9 so that differential high pressure relationship is at al1 times maintained between the pressure of the fluid Supplied to the inner and outer ends of the motor vanes |9'; that is to say, the pressure of the iluid supplied to the inner ends of the vanes i9' at all times exceeds by a substantially constant, predetermined amount the pressure of the iluid supplied \to the outer ends thereof, The amount of this pressure diierence may be adjusted as required by means of the screw 5I and is preferably kept at the lowest value producing satisfactory operation of the vanes I9' oi" the motor B. In practice it has been found that pressure differential ciency of the transmission.

volume of fluid passing through the valve C. 'I'he -port 5| and outlet port 52.

'of from ten to thirty-live or forty pounds per sq. in. is usually sumcient although diil'erential pressures up to and including seventy-five pounds per sq. in. have been successfully employed in systems oi' this general character.

The present invention has numerous advantages. For example, the vane type pump supplies fluid at two different pressures, thus making it unnecessary to pass the entire output of the pump through a pressure reducing or diierential pressure valve, thus increasing the eili- Moreover, when a variable capacity vane pump is employed, as in the present instance, the volume of fluid delivered at each of the two relative pressures is varied in corresponding or substantially proportional amounts sothat'any change in one will produce a corresponding change in the other, thereby assuring an ample supply of fluid at each of these two different pressures and at the same time avoiding any material excess in the volume needed at any. time. In this connection it 'should be noted that the volume oi fluid required by the inner ends of 'the motor vanes I9 will always bear a proportional relationship to the volume of fluid required by the outer ends of said vanes I9', and these two volumes will change proportionately with change fin rotative speed of the rotor I5'. For example, to use purely arbitrary figures in which leakage isneglected, let us assume that a iluld volume of 10 gals. per min. admitted to the outer ends of the vanes I9' causes the rotor l5' to revolve at .600 R. P. M. and that a iluid volume of 1 gal. per min. is then required by the inner ends of the vanes |9'; a uid `volume of 20 gals. per min. would have to be adA mitted to the outer ends of the motor vanes I9' Vto cause the rotor I5' to revolve a-t 1200 R. P. M. and a iiuid volume of 2 gals. per min. would then be required by the inner ends of said vanes I9' at this speed. It will thus be seen that variation in the volume of uid pumped by the outer ends of the pump-vanes I9, in order to alter the speed of motor B, will simultaneously vary the fluid volume supplied to the inner ends of the motor vanes I9' in accordance with the requirements thereof at the changed speed of the motor.

The small differences in the pressures of the uid pumped by the inner and the outer ends of the pump vanes I9. according to the present embodiment, does not adversely aect the operation of the pump A and is so small that it does asumen l 7 not cause undue deflection or increase in wear of the flexible interconnecting track elements 34. As already stated. the volume of fluid that must be supplied to the inner ends of the motors vane l ZI' as illustrated .in themodled end plate 2l" of pag.1311. in which such s single, vane slot port |21' i'slsubstituted for the two pairs of vaneslot ports 21' and Il' of the embodiment of Fig. 3a

Fig. 3a are omitted in .the modified end plate 23" and there is nojfluid connection between the innejr ends of the vanes il' and the outlet ports 2I'.when such modined end plates are employed. The vane `slot port |21 is connected with the supply of differential high pressure fluid by the inner ends of the pump vanes llthis connection being made as through the holes 22'. With this modified arrangement differential high pressure uid is continuously supplied to the inner ends of all the vane slots i8 and itis only necessary to supply differential high 'pressure y fluid to the inner ends of the vanes is' in volume suilicient to make up for leakage inl this portion .of the fluid circuit, and this is a considerably smaller fluid volume than is requiredl with the separate inlet and outlet vane slot ports 21' and 28' respectively, asin Fig. 3a. With thisar rangement the vanes is' are acted upon by the differential high pressure fluid while the outer ends thereof are passing through the low pres` sure or outlet areas of themotor B so that ,wear and friction on the corresponding portions et the vane track are somewhat'greater than with the arrangement of the end plates of Fig. 3a. 'I'he construction of Fig. 3b also has the advantage, however, of somewhat greater simplicity of manufacture.

Another conspicuous advantage of the present invention is that lit makes it possible to provide an extremely compact vane type transmission which is smallerand lighter than can be obf tained with systems and constructions heretofore employed. This will be understood from conand 4a.

The-transmission illustrated in Figs. 4 and 4a includes a pump A land a motor B, the internal parts of which (such as rotors, vanes, shafts,

vane tracks, etc.) are identical with those of the embodiment of. Figs. l, 2, 2a, 3 and 3a. The pump end plates of this embodiment differ from those of Fig. 1, however, in that the ports 25 and 2i extend through the pump end plate 24 and are recessed in the end plate 23: this also applies to the motorend plates 23' and 2l( although it will also be understood that modified end plates of the type illustrated in Fig. 3b may be employed in the motor B if preferred. In this instance, however, the pump A and motor B are housed in casing members-comprising three axially separable parts ill, ill and III, respectively. The

parts ill and III are attached, as by cap screws H3, to the part H2 and said part Il! may be said to be a casing member common to both pump and motor; this facilitates assembly andpermits separate axial adiustment of the parts of the pump and motor units. Fluid is supplied 6 24 through p 7.o able in an enlarged bore or passage |53.

I ply pipe or passage 42 which is connected with the inlet channel 43, as clearly shown in Fig. 4, from which the fluid passes to the pumps inlet ports 2l and-vane slot ports'l'l `of its end plate not illustrated in Fig. 4 but which may be identical with the arrangement described in connection with the embodiment of Fig. l.

uid discharged by the outer ends of the pump `l vanes Il passes through the discharge ports 2l in the pump end plate 24 and into passages ill extending Vaxially through the casing member H2 and connecting with the inlet ports 2l in the end plate 24' of the motor B.- In the present l' instance a separate passage l|30, having the same previously described; the radial passages 2l of general cross-section as'that of the ports 2l and 2l', is provided for each of the pumps outlet sure existing in them.4 With this arrangement iiuid discharged by the outer ends of the pump vanes Il' passes through the straightest and f shortest possible path of travel to the outer ends 25 ofthe motor vanes- Il'. thus reducing power low. f

' Each vane slot port 2l of the pump end plate 24 is connected in a generally similar manner with the corresponding vane slot port 21' of the motor end plate 24' that is axially in line therewith, this connection being 'made through passages |40 which likewise extend axially through the casing member lilas shownl in Fig. 4. In the present embodiment a k,plurality of passages |49 are employed to connect each vane slot port l2l with the corresponding, vane slot port 21' of the motor B in orrler to provide ample areaA for freeviluid flow withoutincreasing the dimensions of the casing ports, and lall of said passages I 40 are connected by asuitable passage Ill (Fig.'4)

to equalize the pressure 'of the fluid therein.

Fluid discharged by the motor vanes I8' passes out through the discharge ports 2i' of the motor end plate 24,' and through'appropriate passages lll (Fig. 4a) into the discharge channel l5' (Figs.

4 and `4a) which in turn is con'nected with the return passage leading to the reservoir, not shown.

As in the embodiment previously described,

pressure of thefluid discharged by the inner sideration of the modification shown inyFlgs. 4

ends of the pump vanes i! is maintained at a pressure exceeding by a substantially constant amount the pressure of the fluid discharged by the outer ends of said vanes I8 and this correlation of pressures is accomplished by a valve mechanism C. In Fig. 4 the valve mechanism C is illustrated as a simple relief valve of the ball and spring type, although it will be understood that a valve of the type shown in Fig. 1, or any w other suitable type, may be employed. As illusg5 instance one of the vane slot ports4 28 of the pump end plate 23 is provided with a suitable opening lwhich connects with a passage IBC leading. to the valves inlet port or passage .iii which is adapted to be closed by a ball |55 freely mov- The contiguous surface of the ball |55 is thus exposed to iluid under the same pressure as that in the vane slot ports'll of the pump end plates and the force thus exerted urges the ball lli away from a reservoir, not shown, through the supfrom its fully closed position in which it is shown in Fig. 4. The bore or passage |53 also contains a3 spring |5| which urges the ball |55 towardvits fully closed position and the force exerted by said spring is supplemented by the force exerted upon said ball |55, in the same direction, by uid under the same pressure as that in the discharge ports 25 of the pump end plates, one of which islconnected with the bore or passage |53 as by a passage |81.`

1With this arrangement the ball |55 moves to regulate the iiow of excess uid pumped by the inner ends of the pumpvanes I9 so that the pressure ot the fluid in the pumps vane slot ports 28 is kept at a value that exceeds the pressure oi' the lluid in the pumps discharge ports 2l by a substantially constant amount determined by the spring |5I. 'I'his regulation is effected, of course, by varying and controlling the iiow and resistance to flow' of iluid from the vane slot port 28 to the discharge port 26, and in this manner acts to provide the desired differential in pressures between the pressures of the uid admitted to the inner and outer ends of the motor vanes I9'. It will frequently be the case that a valve of the ball and spring construction illustrated in Fig. 4` will not maintain the diierential in pressures within the same close limits that can be obtained with other valve structures, such as that illustrated in Fig. 1 for example, but results obtainable with the construction of the valve of Fig. 4 will prove satisthereby urge said motor vanes into contact with said motor vane track.

2. Fluid pressure means comprising a rotary vane type pump and a rotary vane type iiuid motor, said pump and said motor each having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof as the corresponding rotor revolves, said pump and said motor also each having a vane track which the vanes follow as the rotor rotates, means for causing the A outer ends of said pump vanes to pump one uid -volume to the outer ends of said motor vanes,

y means for causing the inner ends of said pump factory in many instances andfthe simplicity,

compactness and low cost o'f its structure recommend its use where practical. In the construction illustrated -in Fig. 4 a pipe plug |64 serves the double purpose of closing the bore or passage |53 and of actingas an abutment piece for the outer end of the spring IGI.

The operation of the embodiment illustrated in Figs. 4 and 4a is substantially the same as that already described in connection with the embodiment of Fig. 1 and will be understood from the foregoing.

jWhile I prefer to employ pumps and motors of the "double or "double-acting type, each of which includes two fluid sections, it will be understood that the invention is not limited to such use and that, for example, multi-section pumps and iiuid motors of other types may be employed as well as pumps and iiuid motors of the single or "single-acting type which include only a single fluid section. It will also be understood that the embodiments of the invention described herein are merely for the purpose of illustrating the invention and that changes (some of whichhave been indicated herein) may be made without departing from .ing the outer ends of said pump vanes to pump one fluid volume to the outer ends of said motor vanes and means for causing the inner ends of said Pump vanes to pump to the inner ends of said motor vanes another iiuid volume at a pressure higher than the pressure of the iiuid volume pumped to the outer ends of said motor vanes to vanes to pump another fluid volume to the-inner ends of said motor vanes to thereby Iurge said motor vanes into contact with said motor vane -track and means for maintaining the fluid pumped by the inner ends of said pump vanes at a pressure higher than but dependent upon the pressure of the uid pumped by the outer ends thereof.

3. Fluid pressure Ameans comprising a rotary yane type pump and a rotary vane type uid motor, said pump and said motor each having a rotor vprovided with a plurality of vanes movable inwardly and outwardly thereof, said pump and said motor also each having a vane track for imparting to the vanes their inward movement, means for causing the outer ends of said pump vanes to pump one fluid volume to the outer ends of said motor vanes, means for causing. the inner ends of said pump vanes to supply to their inner ends of said motor vanes iiuid in excess of the volume required to -urge said motor vanes into contact with the vane track, and means for combining this excess with the fluid volume pumped by the outer ends of said pump vanes.

4. Fluid pressure means comprising a rotary vane type pump anda rotary vane 'type fluid motor, said pump and said motor each having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said pump and said motor also each having a vane track for imparting to the vanes their inward movement, means for causing the outer ends of said pump vanes to pump one fluid volume to the outer ends of said motor vanes,l means for causing the inner ends of said pump vanes to supply to the inner ends ol.' said motor vanes iluid in excess of the volume required to urge said motor vanes into,

contact with the vane track, and means for combining this excess with the fluid volume pumped bythe outer ends of said pump vanes, said last named means comprising valve mechanism active to regulate the ow of said excess uid to maintain the fluid pumped by the inner ends of said vanes at a pressure exceeding by a substantially constant amount the pressure of the iiuid pumped by the outer ends of said pump vanes.

5. In a fluid pressure means of the character indicated, the combination of a rotary vane pump, a rotary vane fluid motor operated by said pump, means establishing direct communication between the inner ends of the vanes of the pump and the inner ends of the vanes of the motor to4 thereby urge said motor vanes into their operating positions independent of the action of centrifugal force, means for causing the inner ends oi' said pump vanes to deliver iiuid in excess of the volume required to urge said motor vanes into said operating positions, means for maintaining the iluid pumped by the inner ends of said pump vanes at a pressure suflicient to move said motor vanes into operating position and means for supthe inner and to the outer ends of said'pump vanes, pump outlet ports for the discharge oi fluid from the outer ends of said pump vanes, separate pump outlet ports for the discharge o! nuid from the inner ends of said Pump vanos, motor inlet ports for n of pressure iluid to the outer ends oi' said motor Yanes, separate motor inlet ports for admitting pressure duid to the iner ends oi said motor vanes.- a first uid connection between said first named pump outlet ports and'said ilrst named motor inlet ports, a second and separate fluid connection between said second named pump outlet ports and said second named motor inlet ports, a third iluid connection` between said nrst andsccond iluid connections, said third iluid connection including a resistance valve, motor outlet ports for the 'essayes 9 outlet ports, motor inlet ports tor admitting pressure iluid tothe outer ends oi said motor venes, J

separate motor inlet ports for admitting pressure .iluld to the inner ends oisaid motor vanes, a nrst fluid connection between said nrst named pump outlet ports and said first named -motor inlet ports, a second iiuid connection between said vane WW pump and a rotary vane type duid motor. said pump and said motor each having a rotor provided with vane slots and vanes movable inner and the outer ends of said motor vanes,

- tor provided with vane slots and vanes movable radially inward and outward therein as the rotor thereof revolves, pump inlet ports and passages for admitting a supply of iiuid to the inner and to the outer ends of said pump vanes, pump outlet ports for the discharge ci iiuid from the outer ends of said pump vanes, separate pump outlet ports for the discharge of rluid from the inner ends oi said pump vanes, motor inlet ports for admitting pressure iiuid to the outer ends of said motor varies. separate `motor inlet ports for admitting pressure iluid to the inner ends of said motor vanes, a first iiuid connection between said nrst named pump outlet ports and said firstl named motor inlet ports, a second and separate fluid connection betweensaid second named pump outlet ports and said second named motor inlet ports, means for maintaining a substantial ly constant diierential pressure in said second iiuid connection above the pressure in said rst fluid connection irrespective oi the pressure in said first fluid connection, and motor outlet ports for uid discharged by said motor venes.

8. Fluid pressure means including a rotary vane type pump and rotary vane type fluid rnctor, said pump and said motor each having a rotor provided with vane slots and vanes movable radially inward and outward therein as the rotor thereof revolves, pump inlet ports and passages for admitting a supply oi iluid to the inner and to the outer ends of said pump vanes, pump outlet. ports for discharge of fluid from the outer ends of said pump vanes, separate pump outlet ports for discharge of uid from the inner ends ci.' said pump vanes, means vfor simultaneously varying the fluid `volumes discharged respective ly into said iirst and said second named pump radially inward and outward therein as the rotor thereof revolvespump inlet ports and passages` for admitting a supply ot iluid to the inner and to the outer ends oi said pump vanes, pump outlet ports for the discharge of iiuid from the outer ends of said pumpl vanes, separate pump outlet ports for the discharge oi fluid from the inner ends oi said pump vanes, motor inlet ports for admission oi pressure fluid to the outer ends of said motor vanes, separate motor inlet ports for continuously admitting pressure iluid to the inner ends oi all ci said motor vanes, a nrst iiuid connection between said rst named pump outlet ports and said ilrst named motor inlet ports, a second and separate iluid connection between said second named pump outlet ports and said second named motor inlet ports. a third fluid con nection between said iirst and said second fluid connections. said third duid connection including a nesistance valve active to maintain in said second iluid connection a pressure greater than the pressure in said iirst iluld connection, and motor outlet ports :for iluid discharged by the outer ends oi' said motor varies. c

l0. Fluid pressure means including a rotary vane type pump and a rotary vane type fluid motor, said pump and saldmotor each having a rotor provided with vane slots and vanes movable radially inward and outward therein as said rotors revolve, an enclosing casing for said pump and motor including a member common to both pump and motor, pump inlet ports and passages Viol' admitting a supply of iiuid to the inner ends and to the outer ends of said pump varies, pump outlet ports for the discharge of iluid from the outer ends of said pump vanes, separate pump outlet ports tor the discharge of iluid from the inner ends of said pump vanes, motor inlet ports for the onv ot pressure iluid to the outer ends oi said motor vanes, separate motor inlet ports for admitting pressure fluid to the inner ends of said motor vanes. a iirst fluid connection necting the outlet ports for the outer ends of said pump vanes with the inlet ports for the outer ends of said motor vanes, a second and separate duid connection formed in said common casing member and connecting the outlet ports for the inner ends'of said pump vane's with the inlet ports for the inner ends of said motor vanes, a third duid connection between said outlet ports for the outer and for the inner ends 'oi said pump vanos, means for maintaining in said second fluid connection a pressure greater than the pressure in said nrst Afluid connection, and motor outlet 'ports for the discharge of nula by said motor vanes.

` 1l. In a nuid pressure means oi the character indicated, the combination of a rotary 'vane pump, a rotary vane iiuid motor operated by said i5v pump, means for admitting a uid supply to the inner and outer ends of said pump vanes. means for supplying to the outer ends of said motor vanes fluid pumped by the outer ends oi said pump vanes, outlet means for the outer ends of -lo said motor vanes, means' establishing direct communication between the. inner ends of the vanes of the pump and the inner ends oi the vanes oi the motor to thereby urge said motor vanes into their operating positions independent-of the action `oi' centrifugal force, and means for causing the inner ends of said pump vanes to deliver iluid tor vanes into said operating positions, said last named means comprising pump vanes the combined areasv of allthe inner ends of which exce'ed the combined areas of the inner ends of all the motor vanes.

l 12. Fluid pressure means comprising a pair of separate rotary piston elements, uid inlet means for the inner and outer ends of the pistons of oneof said elements, iluid outlet means for the outer ends of the pistons of the other oi' said el ents, separate passages establishing comm cation between the outer and inner ends of the pistons .30

of the elements, and means for maintaining the iluid in the passage between the inner ends of the pistons of the-, elements at a pressure greater than but related to theupressure of the iluid in the passage between the outer ends of said pis 35 tons. A Y 1 13. In a fluid pressure means, the combination of a multi-pressure pump supplying two separate fluid volumes of diierent but related pressures. a

rotary vane fluid motor operated by said pump. 40

means for supplying one ot said volumes to the outer ends of the vanes of the motor-and means for supplying the other of said volumes to the in- I ner ends of the vanes oi' the motor and for main taining the pressure thereof at anamount suiiicient to move said motor vanes into operating positions.

14. In a iiuid pressure means, the combination of a vane type uid motor having a plurality o( vanes, a multi-pressure pump supplying two sopa,

arate uid volumes, one a relatively 'large volume* oi one pressure and another a relatively small volume of higher pressure, means for admitting.;

to one end oi.' the vanes said smaller volume og A fluid at said -higher pressureand means tor si. multaneously admitting to the other-ends-oi said vanes said larger voluine o! uid at' said lower pressure to thereby impart rotary motion to Vthemotor, means for correlating the pressures ofsaid. high and low pressure volumes to .o

therebetween a pressure difference suiiicient to move said motor vanes'finto their operating positions, and outlet means' for the ends oi said motor vanes receiving said larger volume oi iiuid at saidlower pressure. .7

in excess of the volume required to urge said mo- 15. Huid pressure means comprising a multisection 'rotary vanetypepump and a multi-seetion' rotary 'vanertype fluid motor operated by said pump. each section of said pump and said motor comprising an inlet area, a working chamber and an outlet area, said pump and said motor.

each having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof in 'a substantially radial direction, said pump and saidv motor also each having a vane track for imparting to the vanes.their inward movement and for guiding said-vanes in their outward movement, means for causing the outer ends .or said pump vanes to pump one fluid volume as they pass from the inlet area to the outlet area of each section of said pump, means for causing the innerends of said pump vanes to pump another iiuid volume as the outer ends of said pump vanes pass through the outlet area of each section of said pump, means for admitting the fluid pumped by the inner ends of said pump vanes to the inner ends of said motor vanes as the outer `ends of said motor vanes pass through the inlet `area of each section ot said motor to" thereby urge said motor vanes into contact with the vane track ot said motor, means for admitting the iiuid pumped by the outer ends of said pump vanes to -the outer ends of said motor vanes as said motor vanes pass through the inlet area and working chamberoi' each section of said motor to-thereby impart rotary motion to the rotor of said motor. -means for substantially equalizing the pressure Vof the -iiuid volumespumped by the inner ends'of said pump vanes in all of the sections of said pump,' means for substantially equalizing the pressure of the fluid volumes `pumped by the outer ends of said -pump vanes [each afrotor-,provided with a plurality of vanes movable inwardly and outwardly thereof as the corresponding rotor revolves, said pump and said also each having a vane track which lthe vanes follow-...as the rotor revolves. means ioreausing the outer-'ends o! said pump vanes to pump one iiuid volumeto the outer ends of said motor vanes. means i'or causing the inner ends ot said pump vanes to pump to the inner y of the-motorvanes another iiuid volume at a 4suiii'cient to move said motor vanes into contact witlsaid motor vane track and means for simultaneously varying the fluid4 volumes 'inner and outer ends respectively CHARLES KENDRICK. 

